National Calculation Methodology (NCM) - Scottish Government

Activity Database
6 NCM Databases.
88. The NCM requires the activity definitions for a building to be defined by selection
from a set of standardised activities. For this purpose, the NCM Activity Database
was developed. The database contains a list of building types (see Table 9 for the
full list of building types) and the space types (activities) that typically exist in each
one (see Table 10 for the full list of activity). Each building type has a selection of
the total available activity types to choose from.
89. The NCM divides each building up into a series of zones (following the zoning
rules in paragraphs 83 - 86), each of which may have different internal conditions
or durations of operation. This enables the calculation to be more analytical about
the energy consumption of a mix of uses in a particular building, rather than relying
on a generic type such as “office” or “school”. For instance, an “office” may mean
anything between a set of cellular offices, meeting rooms, and circulation spaces
that are only occupied during the normal working day, and a dedicated 24-hour
call centre. The approach of setting up multiple activity areas allows such buildings
to be defined more correctly.
90. In order to achieve consistency in assessing compliance and producing Energy
Performance Certificates for non-domestic buildings, when the buildings are used
in different actual operating patterns, a number of parameters for each of the
activity areas are fixed for each activity and building type rather than left to the
discretion of users. These parameters 28 are mainly:
a. Heating and cooling temperatures and humidity set points - The heating and
cooling set-points define the conditions which the selected HVAC system will
be assumed to maintain for the period defined by the heating and cooling
schedules.
b. Lighting standards - The illuminance levels (in Lux) which need to be
maintained in each activity area for the period defined by the lighting
schedules. This level of illumination is then provided by the lighting system
selected by the user. In addition to general lighting, some activities are
assumed to have display lighting. The Lux levels, along with the user selected
lighting system, are used to calculate the heat gains from lighting.
c. Ventilation standards - The required fresh air rate for each activity for the
occupied period. This value is used along with the occupancy to calculate the
quantity of ambient air which then needs to be heated or cooled to the required
heating or cooling set-point. Whether or not the activity will include high
28
The data was drawn from respected sources, such as CIBSE recommendations, supplemented and
modified where necessary to cover activity areas not listed in such sources.
30